A science teacher who joked about a pupil performing a sex act with a Smurf has avoided a classroom ban.
Adam Evans also made "beeping noises" as he held a pedometer near a boy to suggest he was a paedophile.
The physics teacher was sacked for gross misconduct from Fazakerley High School in Liverpool in April last year.
While the Teaching Regulation Agency (TRA) hearing found Mr Evans guilty of unacceptable professional conduct, he was spared a ban from the profession.
The hearing in Coventry was told that Mr Evans made the Smurf joke after seeing a pupil's fingers stained with blue ink.
Mr Evans, who is believed to be in his late 20s, also admitted making explicit remarks about a pupil eating a chocolate bar and discussed sexual contact between a 15-year-old boy and a 14-year-old girl.
When a pupil mispronounced "pedometer" as "pee-dometer", Mr Evans reacted by holding up the device and making a bleeping noise.
This caused the boy to reply: "Sir, are you calling me a paedo?"
TRA chief executive Alan Meyrick said he would not ban the popular and respected teacher despite his "comments of an inappropriate and sexual nature in front of pupils".
"Mr Evans accepted that he used humour as a teaching tool but, for this lesson, due to the stresses he was under, he had severely misjudged what was appropriate," the TRA said.
The panel judged that "the conduct complained of was limited to a single lesson and was a misjudgement, albeit a significant one, by Mr Evans following a lengthy period of pressure being placed on him both in a professional and personal capacity".
Mr Evans, who qualified as a teacher in September 2016 but had already been promoted to deputy science head, said he was "disgusted" with himself and "distraught" that one student wanted to avoid his classes.